N-alkyl-morpholines are applied as fungicides in plant protection (DE-PS 1164152 and 1198125 and DD 140112).
A disadvantage of the known agents is that they have only a narrow spectrum of activity, preferentially for mildew fungi (Erysiphales) in cereals. By their phytotoxic side effects they can be used only in a restricted field of application.
The various acylamide derivatives (DD 118 979 and 118 510, DE-PS 2 515 091, 1 448 810 and 2 903 612, GB-PS 1 603 730 and EP 26 873), on the other hand, possess a good efficacy against fungi from the group of Oomycetes, but they are inactive against other plant pathogenic fungi of economical importance.
Furthermore, it is known that benzimidazole- and dithiocarbamate fungicides are applied in plant protection to control fungal diseases (GB-PS 1 193 461, 1 190 614 and 1 000 137). A disadvantage of the benzimidazole fungicides results from the quick appearance of resistance in the target fungus population.
For simultaneous control of different species of fungi the use of a mixture of N-alkyl-morpholines with dithiocarbamates was recommended (DD 111 014).
It is also known that N-alkyl-morpholine derivatives in combination with methyl N-(2-methoxyacetyl)-N-(2,6-xylyl)-D,L-alaninate (HU-PS T/33363) are beneficially used against fungal diseases.